Carburetor



R, F. BRAckE GARBUHETOB Filed Sept. 26, 1925 i 3 Shaw-Sheet 2v PatentedDec. 6, 1932 UNITED STATES PATENT@ oFFrcE ROBERT F. BELGE, F CHICAGO,ILLINOIS, ASSIGNOR TO CURTISS B. Cm, TRUSTEE OE GLENGOE, ILLINOISCARBURETOB This invention relates to carbureting devices for multiplecylinder internal combustion engines, and is expressly designed for thedelivery of fuel through different nozzles for serving differentcylinders of the engine.

Great difficulty is often experienced 1n properly and equallydistributing the fuel and air from a single carburetor to a plurality ofcylinders, so that all of the cylinders Will receive the same quality ofmixture,and will therefore produce explosions of equal length. Theparticular embodiment of my invent'. on here illustrated is associatedwith a carburetor of the fuel lifting ty e, that is, one wherein thesuction derived rom the engine lifts the fuel from a low level supplytank to the carburetor, from which it is delivered to the enginecylinders mixed with air. The particular type of fuel lifting devicehere illustrated is arranged for regulating the flow of fuel to thenozzles of the carburetor, in accordance with the height to which thefuel is lifted from the low level supply tank, by means of a valvelocated in the fuel line and controlled as to its degree of opening by adiaphragm, one side of which is subjected to atmospheric pressure andthe other side to the suction of the engine intake on the carburetornozzles. While it is not essential that this particular type offuel-controlling mechanism be used with my invention, it has particularutility when used therewith since it provides means for maintaining thefuel for delivery to the nozzles at a constant pressure considerablyless than that of the atmosphere, which, as will be later pointed. out,assists in preventing the delivery of fuel from the nozzles of my fuelcarburetor device at times ,a when fuel delivery Afrom the nozzles isnot desired. My invention is illustrated in the accompanying drawings,in which Figure 1 represents an automobile chassis and shows therelative location of the fuel supply reservoir and the fuelfeed andcarburetor mechanism of my invention;

Figure 2 is a vertical section through the valve mechanism which servesto control the air infiow to the engine manifold and the 5G valvemechanism which serves to control the fuel flow to the nozzles and tomaintain the latter under a constant negative head;

Figure 3 is an elevation of my invention as applied to a four-cylinderautomobile engine block; and

Figure 4 is a horizontal section taken on the line 4 4 of Figure 8.

Referring to Figure 1, the chassis there illustrated is of conventionalform and is provided at the rear with a fuel reservoir 6 connected bytubing 7 with the fuel controlling valve 8 illustrated in detail inFigure 2. Pipes 9 and 10 carry the fuel from the fuel regulating valvemechanism 8 to separate nozzles 12 and 13 .mounted in the manifold 14which is attached to the engine block 15. An air valve housing is shownat 16 for regulating the incoming air which branches in the manifold 14and passes. tothe engine block and the cylinders past the-throttlevalves 17 and 18 shown in their wide openpositions in Fi ure 4. i

ith this general outline of my invention I will now describe the detailconstruction of the fuel valve 8 which, as before stated, serves tomaintain a supply of fuel under substantially constant depression andholds it ready for delivery to either of the nozzles which, by thedegree of suction produced thereon, demands a fuel delivery. The housing8 is provided with a cover 20 which screws into the upper portion of thehousin the housing and cover being provided wit registeringcircumferential seats 21 and 22 between which a thin metal diaphragm 23is clamped. The space above this diaphra m is in communication withatmosphere t rough a. bore 24'* in the centrally located plug 24, whilethe space below the diaphragm is in communication with the carburetornozzles through 9@ the pipes 9 and 10. The communication between thespace below the diaphragm and consequently between the pipes 9 and 10and the main low level supply tank 6 is controlled by the valvel 25resting upon a seat 26, the valve being plressed against this seat byspring 27 and aving its upper end in contact with the central portion ofthe dia hragm 23 so that it will be opened thereby w en the diaphragm isdrawn downwardly by suction mi 9 and 10 extending to the nozzles.

derived from the depression in the fuel lilrils e spring 28 acts uponthe diaphrao'm 23 to assist in opposing the movement of the diaphragmunder the influence of the suction derived from the depression in thefuellines 9 and 10. The lower portion of the valve body 8 is providedwith a fuel inlet port 30 shown in Figure 3 and which communicates withthe annular space 31 (Fig. 2). A screen 33 is interposed in the path offuel between the space 31 and the interior 34 from which fuel passesupwardly into the chamber servin the valve '25.

he air Valve housing ,16 encloses a valve plate 37 mounted upon a stem38 and normally resting upon a circumferential seat 39 formed in thehousing 16. The enlarged lower end of the stem 38 constitutes a piston40 working in the cylinder 41 formed in -the housing 16 and serves as adashpot to yprevent fluttering of the valve 37. The dashpot action ofthis valve also serves toprevent the rapid opening of the valve 37, thusproviding a slightly increased suction in the chamber 42 as the valve 37tends to open, this suction serving, as will be hereinafter pointed out,to provide a slightly enriched mixture at the time the engine isaccelerated. The valve 37 is held normally closed by means of a spring 43 abutting on the one hand with in the hollow portion of the piston 40and on the other hand the under side of the partition separating thecylinder 41 from the air intake passage 44 from which the air is drawnpast the valve 37 when the valve opens. The entrance to the air intakepassage 44 is controlled by a choke throttle of any desired form, thelever 46 being shown as meansfor closing this choke, the purpose ofwhich is to provide a great restriction to the inow of air for startingthe motor. This restriction to the inflow of air, will increase thedepression in manifold and tend to enrich the mixture entering thecylinders, hence starting will be facilitated. A weak spring 45 opposesthe action of the spring 43 and ismade adjustable for the purpose ofdelicately regulating the degree of suction at which the valve 37 opens,this adjustment being important to obtain the correct mixture for idlingthe motor. n The air chamber 42 is in direct communication with thecentral portion of themanifold 14, the latter-.conducting the flow ofair, as before described, to the openings in the cylinder block. A pairof Venturi nozzles 12 and 13 are mounted in direct alignment with theopenings into the engine block. As shown in Fig. 4, the Venturi nozzleconsists of a cylindrical aperture 100, at the base of which is abell-shaped entrance 101, leading to a narn row throat 102. Uponenlargement of the throat, the walls give way to dip 103, which leadsaway to a uniformly enlarged chamber 104, whose mouth is in the throatof Venturi tube 48. Immediately below the dip are small h-oles 1057uniformly spaced in the circumferenc of the tube, communicatingwith theannular space 106 which is the outlet of the fuel pipe 9. -The outeraperture is protected by a cap 107. which is held in position by aCotter-pin 108 engaged in coinciding holes in the cap and hollowcylinder. The lower edge of the cap is perforated to allow entrance ofair. Both nozzles are of similar design and are mounted in the manifoldand are arranged to draw in a small amount of air, the diameter of thethroat of the nozzle being so small that under the idling condition ofthe motor when the air demand is least, the restriction imposed to thepassage of air through the Venturi tubes 12 and 13 will not relieve thevacuum in the manifold 14; there being even under this condition a smallamount of air draw-n -into the manifold through the air Valve 37. Theends of the nozzle Venturi tubes 12 and 13 extend into the throats 'ofother Venturi tubes 47 and 48. The anterior ends of these Venturi tubesreceive theirair from the manifold, whereas, as heretofore described,the anterior ends of the Venturi tubes 12 and 13 receive their air fromwithout the manifold and at atmospheric pressure. Throttle 17 and 18 areeach connected to individual shafts 49 and 50, which are connected tolevers 51 and 52 respectively. These levers being held in contact onewith the other by a spring 53 and being made relatively adjustable by ascrew 54 so that the throttles 17 and 18 may be adjustably closed andopenedto allow the same volume of mixture to be fed to the differentcylinders in the engine, thereby attaining explosionsof equal strengthin the cylinders. This is particularly necessary during the idlingcondition of the motor, at which time a very slight difference in thepositions, of throttles 17 and 18 will make a noticeable difference inthe strength of the explosions. 'lhe two throttles thus described areoperated by means of a linkage not shown, which is preferably connectedwith the end 55 of lever 52.'

In the operation of the motor the nozzles 12 and 13 function very muchas two separate ca rburetorsv with the exception that they are caused tod eliver fuel in unison or synchronisln with the suction stroke of thecylinders which the particular nozzles serve and are caused to withholdtheir fuel during ,non-suction. periods by the arrangement of partshereinafter more fully explained inconnection with the operation of thedevice. In a four-cylinder motor, such asdiagrammatically illustrated inFigure 1, it is customary that the motor valves be arranged so that thesuction strokes of the cylinders occur-in an order causing'alternateperiods of. suction and non-suction for each of the two entrances intothe cylinder block. The ar rangement of suction strokes will usually be(numbering thecylinders 1 to 4 from the front of the engine block) 1, 4,2 and 3, though the order of suction strokes may, in some instances, be1, 2, 3 and 4. In either case, the suction period occurring through thenozzle 12 Will be followed by a non-suction period through that nozzleduring which time a suction period will occur through the nozzle 13followed by a second suction period through the nozzle 12 and a secondsuction period through the nozzle 13. The interior of the manifold 14 ismaintained under a depression controlled by the valve 37 in order thatthere may be suilieient suction for lifting the fuel from the low levelsupply reservoir under all conditions of operation of the automobileupon which the carbureting mechanism ofmy invention is installed. Thisdepression or suction in the manifold 14 is maintained by means of thesprings 43 and 45 acting upon the valve 37 at such a degree that thesuction created at the throat of the Venturi tubes 12 and 13 during theidling condition of the motor Will be suflicient to lift fuel through adistance of substantially 40 inches. Such a suction will be maintainedat the throats of the Venturi tubes 12 and 13 when a static suctionequivalent to about 15 inches of gasoline is maintained in the manifold14. The springs 43 and 45 aretherefore given an initial compressionrequiring a suction in the manifold equivalent to about that neces* saryfor maintaining a column of fuel 15 inches high before the valve 37 Willbe raised off its seat to permit the inflow of air into the manifold.'When the engine is idling, therefore, at which time the fuel demand isthe least, a very small amount of air is being taken in past the valve37, but such an amount as does flow past the valve 37 passes alternatelythrough the Venturi tubes 47 and 48. As this air passes through theVenturi tube 47 it creates upon the discharge end of the Venturi tube 12a suction which is slightly enhanced over the static suctionl in themani fold 14 and maintained by the valve 37 and its associated springs.This slightly increased suction on the end of the nozzle 12 tends todraw fuel out of the pipe 10 and into the nozzle 12 at this moment,Whereas the nozzle 13, which at this time is not subject to quite suchsevere suction, does not tend to draw fuel from thepipe 9. As beforedescribed, the pipes 9 and 10 both communicate with the chamber beneaththe diaphragm 23 which controls the fuel valve 25. This diaphragm andits associated fuel valve and springs 27 and 28 serve to maintain a fueldepression in the chamberwvith which the pipes 9 and 10 communicate,which depress sion is substantially Aconstant under variations in fueldemand as Well as under variations in fuel lift. 1n assuming for thepurfor creating slightly enhanced suctions at the throats of the Venturitubes 12 and 13 Where the fuel discharges into thcair ath, in order`that fuel delivery will occur. he spring 45, which controls the delicateadjustment of the valve 37, is adjusted during the periods when any airflows through the large Venturi tubes 47 and 48. Normally the staticsuction. on the ends of the Venturi tubes 12 and 13 causes a suction attheir throats 102 and in Ithe chamber below the diaphragm23, and underthis condition no fuel will be drawn out of the pipes'9 and 10 into thenozzles 12 and 13 excepting during the periods when the suction aboutthe ends of the nozzles 12 and 13 is enhanced by the flow of air throughthe Venturi tubes 47 and 48. As the throttles 17 and 18 are opened, the:dow of air to the cylinders increases, the suction on the ends of thenozzles 12 and 13 increases and consequently causes a proportionatelylarger amount of fuel to be drawn into the nozzles at each suctionstroke. But between the suctien strokesat the time when only staticsuction is acting upon the ends of the nozzles 12 and 13, the flow offuel to the throats of these nozzles either entirely ceases or be comesso slight as to be negligible in the operation of the motor.. lfVhat lhave provided therefore by my arrangement of noz zles is anautomatically operating fuel injection system receiving air from acomino-n manifold', which is provided with a regulatn ing valve which byits regulating action con-` trols the amount of fuel delivered from theplurality of nozzles in timed relation with the suction strokes of themotor. lt will he understood that thesamesystem as herein disclosed maybe applied to any number of cylinder inlets. ,For example, there maj/ hea nozzle corresponding to 12 and a throttle corresponding to 17 for eachcylinder of the motor instead of, as here illustrated, for each pair ofcylinders, and the device, Without other alteration than multiplication,may be used on a four, site, eighter twelve-cylinder motor. It will alsobe understood that structural changes may be made without de partingfrom the spirit or scope of the invention and if, on account ofvariation in level between the nozzle corresponding to 12 and the nozzlecorresponding to 13 located at the extreme opposite ends of a commonmotor, the delivery is caused to be greater at one end than the other,the fuel feeding openings into -one nozzle or the other may be madelarger to compensate for this difference in level of the two nozzles or,if desired, more than one iis lil?

diaphragm control valve may be used, each diaphragm control valveserving either one; or more nozzles. It will also be understood that ifit becomes desirable, in order to prevent back flow of fuel in pipescorresponding to 9 and l0, automatically operating check valves may beprovided in these pipes permitting the iow of fuel in the directiontoward the carburetor nozzles but preventing the flow of fuel in theopposite direction.

I claim:

l. In a carburetor, a plurality of nozzles each having a primary airinduction passage therethrough, a common secondary air induction passagefor said nozzles, an air valve for restricting the flow of air into saidcommon secondary air passage, a chamber from which a lurality of saldnozzles receives fuel including independent directly7 connected conduitsfrom said chamber to each of said nozzles, means to maintain the fuel insaid chamber under depression, said nozzles each having a primary airpassage and the outer and adjacent the induction passage beingpositioned in branches with said secondary air passage and having oneend exposed to the atmosphere, each branch being restricted about itsnozzle whereby the flow of air from the secondary air passage past thenozzle creates a suction on the nozzle for drawing fuel from said fuelchamber.

2. In a carburetor, the combination with an induction passage havingbranches leading to different cylinders of an internal combustionengine, separate nozzles, each having a primary air passage therethroughone for each branch of said induction passage and having one end exposedto the atmosphere, a fuel chamber, branch conduits from said fuelchamber to restrict portions of said nozzles for delivery of fuelthereto, an adjustable diaphragm actuated spring valve having one sidesubject to atmospheric pressure for maintaining the fuel in said fuelchamber under a depression less than atmosphere, a valve controlling theinflow of air to said common induction passage, said, valve heilig soadjusted that the minimum depression which it maintains in the commoninduction passage on a suction stroke in each cylinder when the air ispassing or when there is suction in the induction passage isinsufficient for drawing fuel out of said fuel chamber.

3. In a carburetor, the combination with an induction passagehaving-branches leading to different cylinders of an internal combustionengine, separate nozzles, each having a primary air passagetherethrough, one for each branch of said induction passage, a'fuelchamber, independent branch conduits eX- tending directly from said fuelchamber to said nozzles for delivery of fuel thereto, means formaintaining the fuel in said fuel chamber under a depression less thanatmosphere, and a valve controlling the inflow of air to said commoninduction passage.

4. A carburetor for multiple cylinder en- I gines, comprising asecondary air induction passage having branches extending to the intakeof different cylinders of said engine, an air valve for restricting theflow. of air into said secondary air passage, a fuelcliamber, Venturitubes, one for each branch of said secondary air passage projecting intosaid branches and having their intake end exposed to the atmosphere, afuel conducting passage extending directly from said fuel chamber to thethroat of each of said Venturitubes, and throttle means for controllingthe flow of air through the secondary aii` passage.

5. In a carburetor, the combination with an induction passage havingbranches leading to different cylinders of an internal combustionengine, separate nozzles, one for each branch of said induction passage,a fuel chamber, branch conduits extending directly from said fuelchamber to said nozzles for delivery of fuel thereto, means formaintaining the frel in said fuel chamber under a depression less thanatmosphere, a valve controlling the inflow of air to said commoninduction passage, said valve being so adjusted that the minimumdepression which it maintains in the common induction passage isinsufficient for drawing fuel out of said fuel chamber, the flow of airfrom the common induction passage past said nozzles in the variousbranches serving to alternately create a suction on said particularnozzles past which the air is flowing to withdraw a proper amount offuel from said fuel chamber for mixing with the air to create acombustible mixture.

6. A carburetor having a plurality of nozzles positioned in branch airconduits extending to different cylinders of a. multiple cylinderengine, a common restricted secondary air intake and a common .fuelchamber including directly connected branch conduits from the fuelchamber for said nozzles, means for maintaining the fuel in said fuelchamber under depression, means for restricting the flow of air to thecommon secondary air intake passage to such an extent as to create astatic suction on the nozzles in the branches to the various cylinders,which suction is insufficient for overcoming the depression in the fuelchamber, the alternate flow of air past the nozzles, however, at thetime of the suction stroke of the particular cylinder served by aparticular nozzle acting to increase the static suction in the secondaryair intake passage sufficient to draw fuel from the fuel chamber andoutI of the particular nozzle.

7. A carbureting device for multiple cylinder engines comprising aninduction passage having branches extending to the intake of differentcylinders of said engine, a separate throttle for each branch, a nozzlefor each branch anterior to the throttle in said branch, a Venturi tubein each branch into the throat on which the nozzle for its branchextends, each nozzle having its outer end provided with restrictedcommunication to the atmosphere, and a common fuel chamber havingseparate fuel passages extending directly therefrom to each of saidnozzles at the restricted portions thereof, from which fuel isindividually fed to said nozzles.

8. A carburetor having means of connection with an air induction passageof an internal combustion engine, an air inlet for the passagecommunicating directly with the at-A mosphere, 'a fuel chamber having aconduit extending directly therefrom in communication with the passage,means to maintain the fuel in said chamber under depression less.

than atmospheric and a valve for regulating the inflow of air to the airinduction passage. 9. A carburetor having means of connec.

tion With an intake manifold of an internalcoinbustion engine, an airinlet for the pas `sage communicating directly with the atmosphere, afuel chamber having a lead extending directly therefrom to the passage,means to maintain the fuel in said chamber underdepression less thanatmospheric and a dash pot controlled valve for regulating the Asupplyof atmospheric air to the air induction passage to maintain said passageunder depression to provide sufficient suction for lifting the fuelunder all conditions of operation.

10. A carburetor including an air valve comprising a housing havin aninlet and a seat above the inlet, the ousing having means of connectionwith an air induction passage of an internal combustion engine, a valvecooperating With said seat, a spring controlled dash pot for said valve,another s ring opposing the rst spring, means for ad]usting the tensionof said springs, a fuel valve including a diaphragm exposed toatmospheric pressure centrally, a spring acting on said diaphragm at theside opposite that exposed to atmospheric pressure', a passage throughthe valve having a seat adjacent the diaphra In, a valve seated againstthe seat and adapte to be unseated by the diaphragm, a fuel chambercontrolled by said valve and having communication with each end of theintake manifold, a Venturi tube in each end, a nozzle in each endextending into the restricted portion of the Venturi tube, each nozzlehaving its outer end directly exposed to atmosphere, and means forsimultaneously regulating the induction through each end of the intakemanifold.

l11. A carburetor having means of connection with an induction passageof an intel'-A nal combustion engine, a fuel chamber includin directlconnected leads from said :fuel amber or communicating with the passage,means to maintain the fuel in said chamber under depression, a valve forcontrolling the inflow of air to the induction passage, means to providegreat restriction to the infiow of air to the induction passage formotor starting, and a vdash pot associated

